The nostalgic era of bottled milk is usually associated with the thick layer of cream (the “cream”) or the colored aluminum lids. Since milk wasn’t industrially homogenized back then, the natural fat content collected at the neck of the bottle – the hallmark of real milk.

The cream layer: In non-homogenized milk, the fat droplets rose to the top, forming the creamiest, thickest layer of cream directly under the lid.

The colored aluminum lid: The color of the lid clearly indicated the contents and fat content (e.g., silver/red for whole milk, blue for skim milk, and gold or patterned for cream and cocoa).

The obligatory rinsing and return: The bottles had to be rinsed immediately after use; otherwise, the milk would dry inside, and they wouldn’t be accepted for return.
… You shook the bottle before drinking, or rather, you poured off the thick liquid from the surface.